ArcCHECK结合3DVH在容积旋转调强放疗剂量验证中的应用研究

Application of Arc CHECK Combined with 3DVH in Volumetric Modulated Arc Therapy Dose Verification

目的探索Arc CHECK结合3DVH在容积旋转调强放疗(Volume Rotation Intensity Radiotherapy,VMAT)剂量验证中的应用。方法随机选取20例肿瘤患者,其中鼻咽癌5例,食管癌和肺癌各5例,直肠癌5例。使用Pinnacle3 Version 9.8计划系统(TPS)设计双弧VMAT计划,将计划移植到Arc CHECK模体上重新计算剂量,Arc CHECK模体下出束测量,评估每例患者的γ通过率,然后使用3DVH软件重建靶区和危及器官的剂量分布,与TPS计算结果比较剂量体积参数的偏差。结果20例患者VMAT计划的γ通过率平均值为(98.1±1.1)%,除了1例鼻咽癌患者的低于95%以外,其余病例的γ通过率均>95%。靶区PTV的D_(2%)、D_(98%)、D_(50%)、D_(mean)偏差均在3%以内;危及器官方面,鼻咽癌有1例左、右晶体D_(max)偏差分别在8.63%和7.01%,直肠癌有2例左、右股骨头V_(50)偏差大于5%,其余病例的危及器官剂量体积偏差均小于5%。结论Arc CHECK结合3DVH在VMAT剂量验证中可以提供更多的剂量分布信息,有助于提高临床肿瘤放疗的安全保障。

Objiective To study the application of ArcCHECK combined with 3DVH in volumetric modulated arc therapy(VMAT)dose verification.Methods Twenty cancer cases were randomly selected,including five nasopharyngeal carcinoma cases,five esophageal cancer and lung cancer cases respectively,and five rectal cancer cases.Double arc VMAT plans were designed with Pinnacle3 Version 9.8 treatment planning system(TPS)and transplanted to the ArcCHECK phantom to recalculate the dose.The ArcCHECK phantom was used to measure the beam output,and the gamma passing rate of each patient was evaluated.Then the dose distribution of target and organs at risk were reconstructed by 3DVH software,and the deviation of dose volume parameters were compared with that of TPS.Results The average gamma passing rates of VMAT plans in twenty patients were 98.1%±1.1%.Except for one of the patients with nasopharyngeal carcinoma,the gamma passing rates in the remaining cases were more than 95%.The deviations of D2%,D98%,D50%,Dmean of PTV were less than 3%.In organs at risk,the Dmax deviations of left and right crystal in one nasopharyngeal carcinoma case were 8.63%and 7.01%,respectively.For two rectal cancer cases,the V50 deviations of left femoral head and right femoral head were more than 5%,and the dose volume deviations of other cases were less than 5%.Conclusion ArcCHECK combined with 3DVH in VMAT dose verification can provide more dose distribution informations,which help to improve the safety of clinical tumor radiotherapy.